How does a Wolf-Rayet star become a magnetar?

HD 45166 Artist's impression

This artist’s impression shows HD 45166, a massive star recently discovered to have a strong magnetic field of 43,000 gauss, the strongest magnetic field ever detected in a massive star. An intense wind of particles blown away from the star is trapped by this magnetic field, enveloping the star in a gaseous envelope as shown here. Credit: ISO/L. calzada

Explore the origins of Magnetar

New findings centered on observations and models of stellar evolution of the hot, helium-rich Wolf-Rayet star indicate that it is set to produce a magnetar when it experiences a supernova explosion. These results provide a deeper understanding of the process of formation of magnetars, which are the most magnetic entities in the universe.

Understanding magnetars and neutron stars

A magnetar is a specialized type of neutron star that has an extremely strong magnetic field. Normally, neutron stars arise from supernova events where the core of a massive star collapses. However, the origins of magnetars remain unclear.

One theory proposes that during a supernova explosion, an amplification of the magnetic field within the massive core of the progenitor star could lead to the formation of a magnetar. However, such strong magnetic fields had not previously been detected in evolved stars that have the potential to transform into neutron stars after the explosion.

A massive helium magnetar goes supernova

This artist’s impression shows how, in a few million years, HD 45166 will explode as an extremely bright, but not particularly active supernova. During this explosion, the star’s core will contract, trapping and concentrating the star’s already overstretched magnetic field lines. Credit: NOIRLab/AURA/NSF/P. Marienfeld / M. my time

Discover HD 45166

Tomar Shinar and his research team turned their attention to HD 45166, a binary system consisting of a main sequence star and a Wolf-Rayet companion star. Wolf-Rayet stars are the exposed helium core of a massive star, having lost its outer hydrogen layers. Using spectroscopic polarization observations from the Canada-France-Hawaii Telescope and archival spectra from various other instruments, Schinard and colleagues determined that the Wolf-Rayet component of HD 45166 has a mass of about two solar masses and has a large magnetic field. from 43 kg.

Artist's impression of the newly formed Magentar

This artist’s impression shows the eventual fate of HD 45166 after its core collapsed, creating a neutron star with a magnetic field of about 100 trillion gauss, the strongest type of magnet in the universe. Credit: NOIRLab/AURA/NSF/P. Marienfeld / M. my time

From observations to models of stellar evolution

Based on stellar evolution models and integrating the data gained, the research team concluded that this Wolf-Rayet component is destined to collapse into alien life. neutron star. Their calculations indicate that maintaining the magnetic flux during this core collapse would increase the strength of the magnetic field, putting it well within the range of what has been observed for magnetars.

The authors conclude, “Our observations and models of stellar evolution indicate that the Wolf-Rayet component could be a direct ancestor of the magnetar.”

More about this research:

Reference: “A massive helium star with a magnetic field strong enough to form a magnetar” by Tomer Shinar, Greg A. Wade, Pablo Marchant, Stefano Bagnolo, Julia Bodensteiner, Dominic M. Bowman, Avishai Gilkes, Norbert Langer, Andre Nikola-Cheney, Lydia Uskinova, Timothy van Rith, Hughes Sanna, Nicole St. Louis, Alexandre Soares de Oliveira, Helge Todd and Silvia Tonin, August 17, 2023 Sciences.
doi: 10.1126/science.ade3293

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